You've done well: first violin lesson? (4,1,3)
I believe the answer is:
take a bow
This clue is a double definition.
'you've done well' is the first definition.
'first violin lesson?' is the second definition.
(used for playing stringed instruments)
(Other definitions for take a bow that I've seen before include "to acknowledge admirers" , "Acknowledge applause with bodily movement" , "Acknowledge applause as entertainer does" , "Before playing, cellist must" , "Acknowledge praise or accept credit" .)